Jelčić Rukavina Marija, Gabrijel Ivan, Netinger Grubeša Ivanka, Mladenovič Ana
Faculty of Civil Engineering, University of Zagreb, Fra Andrije Kačića Miošića 26, 10000 Zagreb, Croatia.
Faculty of Civil Engineering and Architecture Osijek, University Josip Juraj Strossmayer of Osijek, Vladimir Prelog Street 3, 31000 Osijek, Croatia.
Materials (Basel). 2022 Mar 17;15(6):2222. doi: 10.3390/ma15062222.
This paper presents an experimental investigation of the compressive behavior of high-strength self-compacting concrete exposed to temperatures up to 600 °C. Ten different concrete compositions were tested, in which part of the cement (by weight) was replaced by three different mineral additives (5-15% metakaolin, 20-40% fly ash and 5-15% limestone). The stress-strain curves, compressive strength, modulus of elasticity and strain at peak stress were evaluated from uniaxial compression tests. Scanning electron microscope micrographs were also taken to evaluate the damage caused by the high temperatures. A sharp decrease in mechanical properties and an increase in peak strain were observed already after 200 °C for all mixes tested. The different mineral additives used in this study affected the variations of residual compressive strength by 24% and peak strain by 38%, while the variations of residual modulus elasticity were 14%. Comparing the obtained results with the recommendations for compressive strength given in regulatory code EN 1992-1-2 for high strength concrete, it can be concluded that the strength loss observed in EN 1992-1-2 at temperatures up to 400 °C is too conservative. The Popovics model for the relationship between stress and strain provided a good approximation for the experimentally determined stress-strain curves at different temperatures.
本文介绍了对暴露在高达600℃温度下的高强度自密实混凝土抗压性能的试验研究。测试了十种不同的混凝土配合比，其中部分水泥（按重量计）被三种不同的矿物添加剂替代（5%-15%偏高岭土、20%-40%粉煤灰和5%-15%石灰石）。通过单轴压缩试验评估应力-应变曲线、抗压强度、弹性模量和峰值应力处的应变。还拍摄了扫描电子显微镜照片以评估高温造成的损伤。对于所有测试的混合料，在200℃后就已观察到力学性能急剧下降且峰值应变增加。本研究中使用的不同矿物添加剂使残余抗压强度的变化达24%，峰值应变的变化达38%，而残余弹性模量的变化为14%。将所得结果与欧洲规范EN 1992-1-2中给出的高强度混凝土抗压强度建议进行比较，可以得出结论，EN 1992-1-2中在高达400℃温度下观察到的强度损失过于保守。应力与应变关系的波波维奇模型很好地近似了不同温度下通过实验确定的应力-应变曲线。
